Change TRIGGERS DEFINER in MySQL

change_definer.sh

##
## Create mysql triggers dump
## We add DROP TRIGGER IF EXISTS with option --add-drop-trigger
## This option is supported only by mysqldump as supplied with MySQL Cluster. It is not available when using MySQL Server 5.5.
## If you don't need password dont use -p option.
##
mysqldump -u <USERNANME> -p --routines --add-drop-trigger --no-create-info --no-data --no-create-db --skip-opt <database> > outputfile.sql

##
## Change old DEFINER with sed command
## Or use your prefered editor to do that
## Exemple : `olduser`@`%` -> `newuser`@`localhost`
##
sed -i -e 's/OLD_DEFINER/NEW_DEFINER/g' outputfile.sql

##
## Import all new triggers in the database
## If you don't need password dont use -p option.
##
mysql -u <USER> -p <DATABASE_NAME> < outputfile.sql

The param --add-drop-trigger doesn't work with all mysql versions

This option is supported only by mysqldump as supplied with MySQL Cluster.
It is not available when using MySQL Server 5.5.
https://dev.mysql.com/doc/refman/5.5/en/mysqldump.html#option_mysqldump_add-drop-database